5-lipoxygenase is an enzyme involved in the in vivo synthesis of leukotrienes and 5-hydroxy-eicosatetraenoic acid (5-HETE). These compounds are believed to be involved in the outbreak of various diseases, including allergic diseases such as asthma, inflammation, myocardial infarction, nephritis, scabies and gout.
Therefore, a compound capable of inhibiting 5-lipoxygenase is useful in the treatment and prevention of various diseases, including allergic diseases such as asthma, inflammation, myocardial infarction, nephritis, scabies and gout.
Examples of compounds capable of inhibiting 5-lipoxygenase include caffeic acid and its methyl ester (cf. Biochim. Biophys. Acta., 792, 92 (1984)). However, the lipoxygenase inhibition effects of these compounds are unsatisfactory.
As a result, the 5-lipoxygenase inhibition effect of caffeic acid has seen enhanced by converting the carboxylic acid moiety thereof into derivatives (cf. EP-A-0163270). However, these derivatives have a dihydroxybenzene structure which causes a disadvantage in that they are liable to be metabolized in vivo.